The present invention relates to a method for manufacturing a filter element, in which a retaining member and the other members such as a sealing member made of resin are secured to a filter.
In general, a filter such as an air filter and an oil filter is secured to a member having a high rigidity, such as a retaining member to compose a filter element to be used. Because the filter as manufactured is formed of material having a relatively low rigidity such as filter paper, and it is therefore difficult to mount such a filter by itself to the other member or provide a sufficient air-tightness between the filter and the other member.
In view of easy formability, resin is normally used for forming the above-mentioned member having a high rigidity. An insert injection is often applied to secure the rigid member on the filter.
Such an insert injection can be applied to manufacture of the filter having a simple shape. However, the insert injection may not be applied to manufacture the filter having a complicated shape. More specifically, some consideration is needed to bring the filter into contact with the mold so as to prevent resin from spreading over any portions of the filter, excluding its portions to which resin body is to be formed. The complicated shape of the filter however leads to complication of the mold. There may be a case in which the mold cannot be formed due to its complexity, causing a problem. When an attempt is made to form a resin-molded body on each of the opposite ends of a tubular filter having a complicated shape such as a chrysanthemum shape by the insert injection, a mold placed in the filter cannot be removed, thus causing a problem. It is substantially impossible to apply the insert injection to the opposite ends of such a filter.
An object of the present invention, which was made in view of the above-mentioned problems, is therefore to provide a method for manufacturing a filter element having a resin-molded frame, which permits to easily form the resin-molded frame, even when the filter has a complicated shape.
In order to attain the aforementioned object, a method of the present invention for manufacturing a filter element, comprises the steps of:
semi-curing resin in a prescribed shape to prepare a semi-cured resin;
inserting forcedly at least one part of a filter into said semi-cured resin; and
curing said semi-cured resin into which said at least one part of said filter has been forcedly inserted.
According to the present invention, a part of the filter is inserted into the semi-cured resin, and then, the semi-cured resin is completely cured. As a result, a mold, which provides a prescribed shape of resin during semi-curing the resin, suffices. A complicated shape of the filter does not lead to complication of the mold. It is therefore possible to form a molded body of resin, leading to an easy manufacture of the filter element at a low cost, even when the filter has a complicated shape.
The filter element of the present invention may preferably be applicable in case where the filter is a tubular filter and at least one part of the filter, which is to be forcedly inserted into the semi-cured resin, is opposite ends of the tubular filter. It has been substantially impossible to apply the insert injection to the opposite ends of the tubular filter, especially the tubular filter having the complicated shape to form a molded resin. It is therefore possible to apply the present invention to formation of the molded resin on the opposite ends of the tubular filter, thus putting the technical effects of the present invention to practical use.
In the method of the present invention for manufacturing the filter element, the above-mentioned resin and material for the filter may preferably be formed of same material. The feature that the above-mentioned resin, i.e., a member (such as an outer frame), which is formed on a part of the filter and has a high rigidity, and the material for the filter are formed of the same material, makes it unnecessary to separate the filter from the outer frame or the other structural component, when the filter element is recycled. It is therefore possible to recycle the filter element as it is, thus leading to an effective recycling system.
Another object of the present invention is to provide the filter element, which is manufactured by carrying out the above-mentioned method for manufacturing the filter element. A mold for such a filter element is simpler than a mold for the conventional filter element in which the molded resin is formed by the insert injection, thus reducing the manufacturing cost of the mold. No time is required to remove the mold, providing advantages in costs. In addition, it is possible to form the resin frame on the filter having a complicated shape such as a chrysanthemum shape so as to provide the filter element in which supporting members made of resin are formed on the opposite ends of the filter, although such a formation of the resin frame cannot be performed by the conventional technique.
Further another object of the present invention is to provide a mold for manufacturing a filter element, comprises:
a supporting member for supporting a filter so that at least one part of said filter is exposed; and
a semi-curing mold member for semi-curing resin in a prescribed shape, said semi-curing mold section having a holding section for holding at least a semi-cured resin and a removable section, which is removed to expose at least one part of said semi-cured resin, said removable section being disposed between an exposed part of said filter and said holding section, and said holding section being disposed so that said exposed part of said filter comes into contact with an exposed-part of said semi-cured resin, after removal of said removable section.
According to such a mold, it is possible to insert quickly the part of the filter into the semi-cured resin during semi-curing the resin, to form the molded resin, even when the resin has a relatively short curing time. More specifically, resin is first supplied into the semi-curing mold member. Then, the resin is semi-cured into a semi-cured state. After completion of the semi-curing step, the removable section of the semi-curing mold member is removed. Removal of the removable section causes the part of the filter, which is exposed from the holding section, is placed in a position where the part of the filter can come into contact with the semi-cured resin, which has been exposed through the removal of the removable section. Then, the part of the filter, which is exposed from the holding section, is inserted quickly into the semi-cured resin as exposed. The semi-cured resin is then cured completely. As a result, the molded resin can be formed on the part of the filter in a short period of time. It is therefore possible to easily manufacture the filter element with the use of the mold of the present invention, even when the resin has a relatively short curing time.
The method of the present invention for manufacturing the filter element is characterized by comprising the steps of: semi-curing the resin in the prescribed shape to prepare the semi-cured resin; inserting forcedly at least one part of the filter into the semi-cured resin; and curing the semi-cured resin into which the at least one part of the filter has been forcedly inserted. The mold suffices to semi-cure the resin in the prescribed shape, leading to the simple structure, even when the filter has a complicated shape. It is therefore possible to form the molded resin on the filter, thus providing effects of manufacturing easily the filter element at a low cost, even when the filter has a complicated shape.